Disclosed herein is a method for determining the arrangement of wave energy converters in a wave power park in a seabed or lake area including the steps of: measuring wavelength and wave direction over a period of time, collecting all values measured for the wavelength and the wave direction in a matrix, statistically determining, from the matrix, a predominant wavelength and a predominant wave direction, and arranging an amount X of wave energy converters at regular intervals over a distance that corresponds to half of the length of the predominant wavelength or a multiple thereof, where the distance is measured in a direction at least more or less parallel to the predominant wave direction.

A power generator or sensor apparatus is provided. Another aspect employs a hybrid triboelectric and electromagnetic generator. In still another aspect, a power generator is used for water wave energy harvesting. A further aspect provides a power generator including an outer housing with an electrical conductor on an exterior thereof, radial overlapping electrodes located within the housing with a dielectric layer between the electrodes, a plate linearly moveable within the housing, at least one magnet affixed to the plate, and at least one spring biasing the plate within the housing. Moreover, an aspect of the present power generator includes a modularized connection configuration to linearly secure together multiples of the housing.

A hydrokinetic electric generator system for use in water that includes a first generator located inside a submersible first housing with fore and aft sections with respective fore and aft attachment points, a center of mass of the first generator located between the fore and aft attachment points, the first generator having a shaft extending out the aft section of the first housing with a turbine attached to the shaft, a flotation support structured to float on the water, and a first cable having a first end attached to the flotation support and a second end attached to the first attachment point on the fore section, and a second cable having a first end attached to the flotation support and a second end attached to the second attachment point in a manner to permit the system to change position in response to changes in direction of water current.

An energy-recovery system has an energy-recovery turbine to receive a flow of water from a water line to which the turbine is connected and to generate electric power from the flow of water while also regulating water pressure in the water line. The system also includes a pressure-regulating valve (PRV) connected in parallel with the turbine to regulate the water pressure in the water line only when the turbine is inoperative. The system includes a spiral water-flow adapter having a water inlet for connecting to an upstream portion of the water line and a water outlet for connecting to a downstream portion of the water line, the spiral water-flow adapter directing the flow of water from the water inlet into the turbine and then to the water outlet.